Ancestral Regulatory Circuits Governing Ectoderm Patterning Downstream of Nodal and BMP2/4 Revealed by Gene Regulatory Network Analysis in an Echinoderm

English version České info

Echinoderms, which are phylogenetically related to vertebrates and produce large numbers of transparent embryos that can be experimentally manipulated, offer many advantages for the analysis of the gene regulatory networks (GRN) regulating germ layer formation. During development of the sea urchin embryo, the ectoderm is the source of signals that pattern all three germ layers along the dorsal-ventral axis. How this signaling center controls patterning and morphogenesis of the embryo is not understood. Here, we report a large-scale analysis of the GRN deployed in response to the activity of this signaling center in the embryos of the Mediterranean sea urchin Paracentrotus lividus, in which studies with high spatial resolution are possible. By using a combination of in situ hybridization screening, overexpression of mRNA, recombinant ligand treatments, and morpholino-based loss-of-function studies, we identified a cohort of transcription factors and signaling molecules expressed in the ventral ectoderm, dorsal ectoderm, and interposed neurogenic (“ciliary band”) region in response to the known key signaling molecules Nodal and BMP2/4 and defined the epistatic relationships between the most important genes. The resultant GRN showed a number of striking features. First, Nodal was found to be essential for the expression of all ventral and dorsal marker genes, and BMP2/4 for all dorsal genes. Second, goosecoid was identified as a central player in a regulatory sub-circuit controlling mouth formation, while tbx2/3 emerged as a critical factor for differentiation of the dorsal ectoderm. Finally, and unexpectedly, a neurogenic ectoderm regulatory circuit characterized by expression of “ciliary band” genes was triggered in the absence of TGF beta signaling. We propose a novel model for ectoderm regionalization, in which neural ectoderm is the default fate in the absence of TGF beta signaling, and suggest that the stomodeal and neural subcircuits that we uncovered may represent ancient regulatory pathways controlling embryonic patterning.

Vyšlo v časopise: Ancestral Regulatory Circuits Governing Ectoderm Patterning Downstream of Nodal and BMP2/4 Revealed by Gene Regulatory Network Analysis in an Echinoderm. PLoS Genet 6(12): e32767. doi:10.1371/journal.pgen.1001259
Kategorie: Research Article
prolekare.web.journal.doi_sk: https://doi.org/10.1371/journal.pgen.1001259

Souhrn

Zdroje

1. ChristiaenL

DavidsonB

KawashimaT

PowellW

NollaH

2008 The transcription/migration interface in heart precursors of Ciona intestinalis. Science 320 1349 1352

2. ImaiKS

LevineM

SatohN

SatouY

2006 Regulatory blueprint for a chordate embryo. Science 312 1183 1187

3. ImaiKS

StolfiA

LevineM

SatouY

2009 Gene regulatory networks underlying the compartmentalization of the Ciona central nervous system. Development 136 285 293

4. OliveriP

DavidsonEH

2004 Gene regulatory network controlling embryonic specification in the sea urchin. Curr Opin Genet Dev 14 351 360

5. LevineM

DavidsonEH

2005 Gene regulatory networks for development. Proc Natl Acad Sci U S A 102 4936 4942

6. StathopoulosA

LevineM

2005 Genomic regulatory networks and animal development. Dev Cell 9 449 462

7. DavidsonEH

RastJP

OliveriP

RansickA

CalestaniC

2002 A genomic regulatory network for development. Science 295 1669 1678

8. OliveriP

DavidsonEH

2004 Gene regulatory network analysis in sea urchin embryos. Methods Cell Biol 74 775 794

9. SodergrenE

WeinstockGM

DavidsonEH

CameronRA

GibbsRA

2006 The genome of the sea urchin Strongylocentrotus purpuratus. Science 314 941 952

10. AngererLM

AngererRC

2003 Patterning the sea urchin embryo: gene regulatory networks, signaling pathways, and cellular interactions. Curr Top Dev Biol 53 159 198

11. DavidsonEH

RastJP

OliveriP

RansickA

CalestaniC

2002 A genomic regulatory network for development. Science 295 1669 1678

12. DubocV

LaprazF

BesnardeauL

LepageT

2008 Lefty acts as an essential modulator of Nodal activity during sea urchin oral-aboral axis formation. Dev Biol 320 49 59

13. DubocV

RottingerE

BesnardeauL

LepageT

2004 Nodal and BMP2/4 signaling organizes the oral-aboral axis of the sea urchin embryo. Dev Cell 6 397 410

14. RangeR

LaprazF

QuirinM

MarroS

BesnardeauL

2007 Cis-regulatory analysis of nodal and maternal control of dorsal-ventral axis formation by Univin, a TGF-β related to Vg1. Development 134 3649 3664

15. AngererLM

OleksynDW

LoganCY

McClayDR

DaleL

2000 A BMP pathway regulates cell fate allocation along the sea urchin animal-vegetal embryonic axis. Development 127 1105 1114

16. CzihakG

1963 Entwicklungsphysiologische Untersuchungen an Echininiden (Verteilung und bedeutung der Cytochomoxydase). Whilhem roux's Archiv EntwickMechOrg 154 272 292

17. ChildCM

1948 Exogastrulation by Sodium Azide and other inhibiting conditions in Strongylocentrotus purpuratus. J Exp Zool 107 1 38

18. PeaseDC

1941 Echinoderm bilateral determination in chemical concentration gradients I. The effects of cyanide, fericyanide, iodoacetate, picrate,dinitrophenol,urethane,iodine, malonate, etc. J Exp Zool 86 381 405

19. CoffmanJA

DavidsonEH

2001 Oral-aboral axis specification in the sea urchin embryo. I. Axis entrainment by respiratory asymmetry. Dev Biol 230 18 28

20. CoffmanJA

McCarthyJJ

Dickey-SimsC

RobertsonAJ

2004 Oral-aboral axis specification in the sea urchin embryo II. Mitochondrial distribution and redox state contribute to establishing polarity in Strongylocentrotus purpuratus. Dev Biol 273 160 171

21. CoffmanJA

ColuccioA

PlanchartA

RobertsonAJ

2009 Oral-aboral axis specification in the sea urchin embryo III. Role of mitochondrial redox signaling via H2O2. Dev Biol 330 123 130

22. BradhamCA

McClayDR

2006 p38 MAPK is essential for secondary axis specification and patterning in sea urchin embryos. Development 133 21 32

23. HardinJ

CoffmanJA

BlackSD

McClayDR

1992 Commitment along the dorsoventral axis of the sea urchin embryo is altered in response to NiCl2. Development 116 671 685

24. AnderssonO

ReissmannE

JornvallH

IbanezCF

2006 Synergistic interaction between Gdf1 and Nodal during anterior axis development. Dev Biol 293 370 381

25. TanakaC

SakumaR

NakamuraT

HamadaH

SaijohY

2007 Long-range action of Nodal requires interaction with GDF1. Genes Dev 21 3272 3282

26. LaprazF

BesnardeauL

LepageT

2009 Patterning of the dorsal-ventral axis in echinoderms: insights into the evolution of the BMP-chordin signaling network. PLoS Biol 7 e1000248 doi:10.1371/journal.pbio.1000248

27. YaguchiS

YaguchiJ

BurkeRD

2006 Specification of ectoderm restricts the size of the animal plate and patterns neurogenesis in sea urchin embryos. Development 133 2337 2346

28. WeiZ

YaguchiJ

YaguchiS

AngererRC

AngererLM

2009 The sea urchin animal pole domain is a Six3-dependent neurogenic patterning center. Development 136 1179 1189

29. SuYH

LiE

GeissGK

LongabaughWJ

KramerA

2009 A perturbation model of the gene regulatory network for oral and aboral ectoderm specification in the sea urchin embryo. Dev Biol 329 410 421

30. Howard-AshbyM

MaternaSC

BrownCT

ChenL

CameronRA

2006 Gene families encoding transcription factors expressed in early development of Strongylocentrotus purpuratus. Dev Biol 300 90 107

31. Howard-AshbyM

MaternaSC

BrownCT

ChenL

CameronRA

2006 Identification and characterization of homeobox transcription factor genes in Strongylocentrotus purpuratus, and their expression in embryonic development. Dev Biol 300 74 89

32. MaternaSC

Howard-AshbyM

GrayRF

DavidsonEH

2006 The C2H2 zinc finger genes of Strongylocentrotus purpuratus and their expression in embryonic development. Dev Biol 300 108 120

33. RizzoF

Fernandez-SerraM

SquarzoniP

ArchimandritisA

ArnoneMI

2006 Identification and developmental expression of the ets gene family in the sea urchin (Strongylocentrotus purpuratus). Dev Biol 300 35 48

34. TuQ

BrownCT

DavidsonEH

OliveriP

2006 Sea urchin Forkhead gene family: Phylogeny and embryonic expression. Dev Biol

35. AngererLM

OleksynDW

LevineAM

LiX

KleinWH

2001 Sea urchin goosecoid function links fate specification along the animal- vegetal and oral-aboral embryonic axes. Development 128 4393 4404

36. LaprazF

RottingerE

DubocV

RangeR

DuloquinL

2006 RTK and TGF-beta signaling pathways genes in the sea urchin genome. Dev Biol 300 132 152

37. McCoonPE

AngererRC

AngererLM

1996 SpFGFR, a new member of the fibroblast growth factor receptor family, is developmentally regulated during early sea urchin development. J Biol Chem 271 20119 20125

38. BradhamCA

OikonomouC

KühnA

CoreAB

ModellJW

2009 Chordin is required for neural but not axial development in sea urchin embryos. Developmental Biology 328 221 233

39. PoustkaAJ

KuhnA

GrothD

WeiseV

YaguchiS

2007 A global view of gene expression in lithium and zinc treated sea urchin embryos: new components of gene regulatory networks. Genome Biol 8 R85

40. CroceJ

LhomondG

GacheC

2003 Coquillette, a sea urchin T-box gene of the Tbx2 subfamily, is expressed asymmetrically along the oral-aboral axis of the embryo and is involved in skeletogenesis. Mech Dev 120 561 572

41. GrossJM

PetersonRE

WuSY

McClayDR

2003 LvTbx2/3: a T-box family transcription factor involved in formation of the oral/aboral axis of the sea urchin embryo. Development 130 1989 1999

42. OliveriP

WaltonKD

DavidsonEH

McClayDR

2006 Repression of mesodermal fate by foxa, a key endoderm regulator of the sea urchin embryo. Development 133 4173 4181

43. CroceJ

LhomondG

GacheC

2001 Expression pattern of Brachyury in the embryo of the sea urchin Paracentrotus lividus. Dev Genes Evol 211 617 619

44. GrossJM

McClayDR

2001 The Role of Brachyury (T) during Gastrulation Movements in the Sea Urchin Lytechinus variegatus. Dev Biol 239 132 147

45. MinokawaT

RastJP

Arenas-MenaC

FrancoCB

DavidsonEH

2004 Expression patterns of four different regulatory genes that function during sea urchin development. Gene Expr Patterns 4 449 456

46. OtimO

AmoreG

MinokawaT

McClayDR

DavidsonEH

2004 SpHnf6, a transcription factor that executes multiple functions in sea urchin embryogenesis. Dev Biol 273 226 243

47. PoustkaAJ

KuhnA

RadosavljevicV

WellenreutherR

LehrachH

2004 On the origin of the chordate central nervous system: expression of onecut in the sea urchin embryo. Evol Dev 6 227 236

48. RottingerE

SaudemontA

DubocV

BesnardeauL

McClayD

2008 FGF signals guide migration of mesenchymal cells, control skeletal morphogenesis [corrected] and regulate gastrulation during sea urchin development. Development 135 353 365

49. AmoreG

YavrouianRG

PetersonKJ

RansickA

McClayDR

2003 Spdeadringer, a sea urchin embryo gene required separately in skeletogenic and oral ectoderm gene regulatory networks. Dev Biol 261 55 81

50. LiX

ChuangCK

MaoCA

AngererLM

KleinWH

1997 Two Otx proteins generated from multiple transcripts of a single gene in Strongylocentrotus purpuratus. Dev Biol 187 253 266

51. HwangSP

PartinJS

LennarzWJ

1994 Characterization of a homolog of human bone morphogenetic protein 1 in the embryo of the sea urchin, Strongylocentrotus purpuratus. Development 120 559 568

52. RottingerE

BesnardeauL

LepageT

2006 Expression pattern of three putative RNA-binding proteins during early development of the sea urchin Paracentrotus lividus. Gene Expr Patterns 6 864 872

53. WikramanayakeAH

PetersonR

ChenJ

HuangL

BinceJM

2004 Nuclear beta-catenin-dependent Wnt8 signaling in vegetal cells of the early sea urchin embryo regulates gastrulation and differentiation of endoderm and mesodermal cell lineages. Genesis 39 194 205

54. Di BernardoMG

GianguzzaF

CiaccioM

PallaF

ColomboP

1989 Nucleotide sequence of a full length cDNA clone encoding for beta-tubulin of the sea urchin Paracentrotus lividus. Nucleic Acids Res 17 5851

55. RottingerE

CroceJ

LhomondG

BesnardeauL

GacheC

2006 Nemo-like kinase (NLK) acts downstream of Notch/Delta signalling to downregulate TCF during mesoderm induction in the sea urchin embryo. Development 133 4341 4353

56. DuloquinL

LhomondG

GacheC

2007 Localized VEGF signaling from ectoderm to mesenchyme cells controls morphogenesis of the sea urchin embryo skeleton. Development 134 2293 2302

57. ManuelM

MartynogaB

YuT

WestJD

MasonJO

2010 The transcription factor Foxg1 regulates the competence of telencephalic cells to adopt subpallial fates in mice. Development 137 487 497

58. MartynogaB

MorrisonH

PriceDJ

MasonJO

2005 Foxg1 is required for specification of ventral telencephalon and region-specific regulation of dorsal telencephalic precursor proliferation and apoptosis. Dev Biol 283 113 127

59. KennyAP

KozlowskiD

OleksynDW

AngererLM

AngererRC

1999 SpSoxB1, a maternally encoded transcription factor asymmetrically distributed among early sea urchin blastomeres. Development 126 5473 5483

60. MiyagiS

KatoH

OkudaA

2009 Role of SoxB1 transcription factors in development. Cell Mol Life Sci 66 3675 3684

61. SakumaR

Ohnishi YiY

MenoC

FujiiH

JuanH

2002 Inhibition of Nodal signalling by Lefty mediated through interaction with common receptors and efficient diffusion. Genes Cells 7 401 412

62. InmanGJ

NicolasFJ

CallahanJF

HarlingJD

GasterLM

2002 SB-431542 is a potent and specific inhibitor of transforming growth factor-beta superfamily type I activin receptor-like kinase (ALK) receptors ALK4, ALK5, and ALK7. Mol Pharmacol 62 65 74

63. DirksenML

JamrichM

1992 A novel, activin-inducible, blastopore lip-specific gene of Xenopus laevis contains a fork head DNA-binding domain. Genes Dev 6 599 608

64. KnochelS

LefJ

ClementJ

KlockeB

HilleS

1992 Activin A induced expression of a fork head related gene in posterior chordamesoderm (notochord) of Xenopus laevis embryos. Mech Dev 38 157 165

65. Ruiz i AltabaA

JessellTM

1992 Pintallavis, a gene expressed in the organizer and midline cells of frog embryos: involvement in development of the neural axis. Development 116 81 93

66. BradhamC

McClayDR

2006 p38 MAPK in development and cancer. Cell Cycle 5 824 828

67. Jafar-NejadH

AcarM

NoloR

LacinH

PanH

2003 Senseless acts as a binary switch during sensory organ precursor selection. Genes Dev 17 2966 2978

68. WallisD

HamblenM

ZhouY

VenkenKJ

SchumacherA

2003 The zinc finger transcription factor Gfi1, implicated in lymphomagenesis, is required for inner ear hair cell differentiation and survival. Development 130 221 232

69. SuzukiA

KanekoE

MaedaJ

UenoN

1997 Mesoderm induction by BMP-4 and -7 heterodimers. Biochem Biophys Res Commun 232 153 156

70. ShimmiO

UmulisD

OthmerH

O'ConnorMB

2005 Facilitated transport of a Dpp/Scw heterodimer by Sog/Tsg leads to robust patterning of the Drosophila blastoderm embryo. Cell 120 873 886

71. OnaiT

YuJK

BlitzIL

ChoKW

HollandLZ

2010 Opposing Nodal/Vg1 and BMP signals mediate axial patterning in embryos of the basal chordate amphioxus. Dev Biol 344 1 377 89

72. DeRobertisEM

2004 Goosecoid and gastrulation.

SternCD

Gastrulation, from cells to embryo London Cold Spring Harbor Laboratory press 581 589

73. MartindaleMQ

HejnolA

2009 A developmental perspective: changes in the position of the blastopore during bilaterian evolution. Dev Cell 17 162 174

74. De RobertisEM

BlumM

NiehrsC

SteinbeisserH

1992 Goosecoid and the organizer. Dev Suppl 167 171

75. OliveriP

TuQ

DavidsonEH

2008 Global regulatory logic for specification of an embryonic cell lineage. Proc Natl Acad Sci U S A 105 5955 5962

76. SharmaT

EttensohnCA

2010 Activation of the skeletogenic gene regulatory network in the early sea urchin embryo. Development 137 1149 1157

77. AffolterM

MartyT

ViganoMA

JazwinskaA

2001 Nuclear interpretation of Dpp signaling in Drosophila. EMBO J 20 3298 3305

78. VerschuerenK

RemacleJE

CollartC

KraftH

BakerBS

1999 SIP1, a novel zinc finger/homeodomain repressor, interacts with Smad proteins and binds to 5′-CACCT sequences in candidate target genes. J Biol Chem 274 20489 20498

79. BehestiH

HoltJK

SowdenJC

2006 The level of BMP4 signaling is critical for the regulation of distinct T-box gene expression domains and growth along the dorso-ventral axis of the optic cup. BMC Dev Biol 6 62

80. LoweCJ

TerasakiM

WuM

FreemanRMJr

RunftL

2006 Dorsoventral patterning in hemichordates: insights into early chordate evolution. PLoS Biol 4 e291 doi:10.1371/journal.pbio.0040291

81. HeM

WenL

CampbellCE

WuJY

RaoY

1999 Transcription repression by Xenopus ET and its human ortholog TBX3, a gene involved in ulnar-mammary syndrome. Proc Natl Acad Sci U S A 96 10212 10217

82. CarreiraS

DexterTJ

YavuzerU

EastyDJ

GodingCR

1998 Brachyury-related transcription factor Tbx2 and repression of the melanocyte-specific TRP-1 promoter. Mol Cell Biol 18 5099 5108

83. Gomez-SkarmetaJ

de La Calle-MustienesE

ModolellJ

2001 The Wnt-activated Xiro1 gene encodes a repressor that is essential for neural development and downregulates Bmp4. Development 128 551 560

84. ItohM

KudohT

DedekianM

KimCH

ChitnisAB

2002 A role for iro1 and iro7 in the establishment of an anteroposterior compartment of the ectoderm adjacent to the midbrain-hindbrain boundary. Development 129 2317 2327

85. Gomez-SkarmetaJL

ModolellJ

2002 Iroquois genes: genomic organization and function in vertebrate neural development. Curr Opin Genet Dev 12 403 408

86. NamJ

SuYH

LeePY

RobertsonAJ

CoffmanJA

2007 Cis-regulatory control of the nodal gene, initiator of the sea urchin oral ectoderm gene network. Dev Biol 306 860 869

87. LeleZ

NowakM

HammerschmidtM

2001 Zebrafish admp is required to restrict the size of the organizer and to promote posterior and ventral development. Dev Dyn 222 681 687

88. WillotV

MathieuJ

LuY

SchmidB

SidiS

2002 Cooperative action of ADMP- and BMP-mediated pathways in regulating cell fates in the zebrafish gastrula. Dev Biol 241 59 78

89. MoosMJr

WangS

KrinksM

1995 Anti-dorsalizing morphogenetic protein is a novel TGF-beta homolog expressed in the Spemann organizer. Development 121 4293 4301

90. ReversadeB

De RobertisEM

2005 Regulation of ADMP and BMP2/4/7 at opposite embryonic poles generates a self-regulating morphogenetic field. Cell 123 1147 1160

91. HorstadiusS

1973 Experimental Embryology of Echinoderms Oxford Clarendon Press

92. YaguchiS

YaguchiJ

AngererRC

AngererLM

2008 A Wnt-FoxQ2-nodal pathway links primary and secondary axis specification in sea urchin embryos. Dev Cell 14 97 107

93. Ben-HaimN

LuC

Guzman-AyalaM

PescatoreL

MesnardD

2006 The nodal precursor acting via activin receptors induces mesoderm by maintaining a source of its convertases and BMP4. Dev Cell 11 313 323

94. RottingerE

BesnardeauL

LepageT

2004 A Raf/MEK/ERK signaling pathway is required for development of the sea urchin embryo micromere lineage through phosphorylation of the transcription factor Ets. Development 131 1075 1087

95. FeldmanB

DouganST

SchierAF

TalbotWS

2000 Nodal-related signals establish mesendodermal fate and trunk neural identity in zebrafish [In Process Citation]. Curr Biol 10 531 534

96. SchierAF

2001 Axis formation and patterning in zebrafish. Curr Opin Genet Dev 11 393 404

97. CamusA

Perea-GomezA

MoreauA

CollignonJ

2006 Absence of Nodal signaling promotes precocious neural differentiation in the mouse embryo. Dev Biol 295 743 755

98. CameronRA

BrittenRJ

DavidsonEH

1993 The embryonic ciliated band of the sea urchin, Strongylocentrotus purpuratus derives from both oral and aboral ectoderm. Dev Biol 160 369 376

99. SummertonJ

1999 Morpholino antisense oligomers: the case for an RNase H-independent structural type. Biochim Biophys Acta 1489 141 158

100. MoultonJD

YanYL

2008 Using Morpholinos to control gene expression. Curr Protoc Mol Biol Chapter 26 Unit 26 28

101. WilsonSI

EdlundT

2001 Neural induction: toward a unifying mechanism. Nat Neurosci 4 Suppl 1161 1168

102. ChangC

HarlandRM

2007 Neural induction requires continued suppression of both Smad1 and Smad2 signals during gastrulation. Development 134 3861 3872

103. Di-GregorioA

SanchoM

StuckeyDW

CromptonLA

GodwinJ

2007 BMP signalling inhibits premature neural differentiation in the mouse embryo. Development 134 3359 3369

104. AlvarezIS

AraujoM

NietoMA

1998 Neural induction in whole chick embryo cultures by FGF. Dev Biol 199 42 54

105. StreitA

BerlinerAJ

PapanayotouC

SirulnikA

SternCD

2000 Initiation of neural induction by FGF signalling before gastrulation. Nature 406 74 78

106. WilsonSI

GrazianoE

HarlandR

JessellTM

EdlundT

2000 An early requirement for FGF signalling in the acquisition of neural cell fate in the chick embryo. Curr Biol 10 421 429

107. BertrandV

HudsonC

CaillolD

PopoviciC

LemaireP

2003 Neural tissue in ascidian embryos is induced by FGF9/16/20, acting via a combination of maternal GATA and Ets transcription factors. Cell 115 615 627

108. HudsonC

DarrasS

CaillolD

YasuoH

LemaireP

2003 A conserved role for the MEK signalling pathway in neural tissue specification and posteriorisation in the invertebrate chordate, the ascidian Ciona intestinalis. Development 130 147 159

109. HudsonC

LemaireP

2001 Induction of anterior neural fates in the ascidian Ciona intestinalis. Mech Dev 100 189 203

110. DarrasS

NishidaH

2001 The BMP/CHORDIN antagonism controls sensory pigment cell specification and differentiation in the ascidian embryo. Dev Biol 236 271 288

111. HudsonC

YasuoH

2005 Patterning across the ascidian neural plate by lateral Nodal signalling sources. Development 132 1199 1210

112. Mieko MizutaniC

BierE

2008 EvoD/Vo: the origins of BMP signalling in the neuroectoderm. Nat Rev Genet 9 663 677

113. DenesAS

JekelyG

SteinmetzPR

RaibleF

SnymanH

2007 Molecular architecture of annelid nerve cord supports common origin of nervous system centralization in bilateria. Cell 129 277 288

114. HudsonC

YasuoH

2006 A signalling relay involving Nodal and Delta ligands acts during secondary notochord induction in Ciona embryos. Development 133 2855 2864

115. SampathK

RubinsteinAL

ChengAM

LiangJO

FekanyK

1998 Induction of the zebrafish ventral brain and floorplate requires cyclops/nodal signalling. Nature 395 185 189

116. LepageT

GacheC

1989 Purification and characterization of the sea urchin embryo hatching enzyme. J Biol Chem 264 4787 4793

117. LepageT

GacheC

1990 Early expression of a collagenase-like hatching enzyme gene in the sea urchin embryo. Embo J 9 3003 3012

118. HarlandRM

1991 In situ hybridization: an improved whole mount method for Xenopus embryos.

KayBK

PengHJ

Methods in Cell Biology San Diego, Calif. Academic Press Inc. 685 695

119. ThisseB

HeyerV

LuxA

AlunniV

DegraveA

2004 Spatial and temporal expression of the zebrafish genome by large-scale in situ hybridization screening. Methods Cell Biol 77 505 519

120. TurnerDL

WeintraubH

1994 Expression of achaete-scute homolog 3 in Xenopus embryos converts ectodermal cells to a neural fate. Genes Dev 8 1434 1447

121. EisenJS

SmithJC

2008 Controlling morpholino experiments: don't stop making antisense. Development 135 1735 1743

122. KennyAP

OleksynDW

NewmanLA

AngererRC

AngererLM

2003 Tight regulation of SpSoxB factors is required for patterning and morphogenesis in sea urchin embryos. Dev Biol 261 412 425

123. LongabaughWJ

DavidsonEH

BolouriH

2005 Computational representation of developmental genetic regulatory networks. Dev Biol 283 1 16

124. LongabaughWJ

DavidsonEH

BolouriH

2009 Visualization, documentation, analysis, and communication of large-scale gene regulatory networks. Biochim Biophys Acta 1789 363 374

125. StenzelP

AngererLM

SmithBJ

AngererRC

ValeWW

1994 The univin gene encodes a member of the transforming growth factor-beta superfamily with restricted expression in the sea urchin embryo. Dev Biol 166 149 158

126. DobiasSL

MaL

WuH

BellJR

MaxsonR

1997 The evolution of Msx gene function: expression and regulation of a sea urchin Msx class homeobox gene. Mech Dev 61 37 48

127. CroceJC

McClayDR

2006 The canonical Wnt pathway in embryonic axis polarity. Semin Cell Dev Biol 17 168 174

128. AngererLM

DoleckiGJ

GagnonML